Box toe



MILLER ET AL 2,033,727

y Mifli" 1o, 1936.

l Box TOE Filed oct. 15, 1952 Patented 1.0, 1936 UNITED( s'm'rss` PATENTori-lcs mont, and Stanley P. Lovell, Newton, assignors to Beckwith pany,Boston,

Mass., 4 Manufacturing Com- 'a corporation of Massa- Application October15, 1932, Serial No. 637,882

f 4 Claims.

, This invention relates to the manufacture of shoe stiieners, and moreespecially box toes of the so-called thermoplastic variety. Box toes ofthis general character are usually conditioned for assembly with theshoe upper, by exposure to moist heat or steam in so-called box toesteamers, wherein they acquire the desired limpness and -mouldabilityfor incorporation into the shoe upper immediately prior to thepulling-over and lasting operations, which conform them to the shape ofthe last, whereupon they are permitted to set or harden in such shape.

In application Serial ,No. 522,794, led March 14, 1931, by Harold S.Miller, there is disclosed a box toe of a thermoplastic character madeup of a textile -fabric backing on which a. thermoplastic compositionconsisting essentially of both rubber and a thermoplastic agent,preferably Montan wax, is placed as an adherent layer, furnishing thedesired qualities of stiffness, flexibility, and resiliency to the boxtoe at normal temperature conditions. When the thermo# plasticcomposition is compounded with such proportions of rubber andthermoplastic agent as will impart what may be termed a semi-softcondition to the box toe, there is little tendency for the layer ofcomposition to separate or break away from the fabric base, even whenthe box toe is subjected to considerable flexing. 0n the other hand,when the stiening composition contains suicient wax or otherthermoplastic agents to impart to the box toe a highdegree of hardnessand stiffness, it is found that the layer of composition tends to breakand slough off from the fabric backing, especially when the box toe isflexed on an arc which places the unsupported surface of the layer undertension. Inother words, the thermoplastic composition is of insumcienttenacity to maintain itself as a coherent layer under exing at normaltemperatures.

Inpacordance with the present invention, we produce a thermoplastic boxtoe wherein a layer of stiening composition made up essentially-ofthermoplastic agent or essentially of rubberand a. thermoplastic agent,preferably Montan wax, is confined between two exible sheet-backings,`preferably of lwoven textile fabric, so -that even when such acomposition is compounded with a view toward imparting a high degree ofstiffness andhardness to the box toe, there is little tendenc'y for thelayer of stiil'ening composition to breakaway by virtue of'its'anchorageto backings on both faces. In other words, the backings conduce to a'non-shatterable condition 'in the composition. no matter in whatdirection the stiiener is flexed.

We proceed substantially as follows when the stiiener is to be onecharacterized by a highY ternal rubber mixer, e. g., one of the Banburyor Werner and Pfleiderer type.o While this mixing operation is goingonor afterv it has been concluded, we preferably add to the mixture anysuitable bulking or filling agent in suitable amount. For'example, wemay add about 200 parts by weight of asbestos liber, Wood our, or thelike. Should cork dust be selected as the ller, a lower proportion needbe used, on account of the low apparent speciflc gravity of cork. In thecase of cork, we would use-a volume o f cork dust corresponding to thatof' the asf bestos fiber or wood flour. If desired, zinc oxide may becompounded with the rubber in comparatively small amount, say 1 part byweight, along with other rubber-compounding agents, such as sulphur,accelerators of vulcanization, etc., for the purpose of modifying thephysical properties of the rubber. It is to be observed that we use l adistinctly preponderant proportion of thermo-y plastic agent, as thisyields a composition which is quite stiff and hard at nornraltemperature conditions. Montan wax, Vwhen used in amount twice that ofthe rubber, yields acomparatively hard and stili composition, onaccountof the hard, brittle nature of this wax at normal temperatureconditions. A stiiening composition compounded as hereinbefore describedlends itself to spreading on suitable backings through the usualcalendering operation. In actual practice, we maintain 4suchcompositions as va bank on a 'pair of calender rolls while feedingprogressively two suitable sheets, preferably textile fabric, into thenip of the 'rolls' so as to receive the composition as an inner layer ofthe desired thickness therebetween. Preferably, the textile fabricemployed is of comparatively coarse weave, so las to furnish openings ormeshes of a size ensuring a firm anchorage of the layer of stiieningcomposition thereto. Thus, we may'advanpounds by weight of :isI

tageously employ so-called Osnaberg fabric having a'yarn count of S2-28,i. e., 32 warp threads and 28 weft threads, to the inch. It is, however,possible to use a. cotton, duck, or twill of comparatively coarse weave.

'I'he plied, stiifened sheet produced as hereinbefore described ispreferably treated on' either or both faces with a suitablewater-soluble adhesive before'it is cut into box toe blanks. Such anadhesive is rendered sticky under the influence of the moist heat towhich the box toe blanks are subjected prior to their assembly with shoeuppers. While it is possible to use various kinds of water-solubleadhesives, including glue, we iind it preferable to treat the fabriclayers with an uncooked starch solution. p We have found that whenuncooked starch is deposited in the fabric and then subjected tosteaming treatment, the starch becomes cooked and yields in situ in thefabric a viscous adhesive, which is not leached from the fabric and doesnot migrate under the action of such water vapor as may condense on thebox toe blanks while they are being steamed.

, While we may use a plain solution of raw starch,

we prefer to add thereto a suitable proportion of dextrine orother'water-soluble adhesive, on account of the fact that the raw starchitself would, after drying, tend to be released as a dust from thefabric. The starch composition which we employ may be one prepared byadding 50 pounds of finely granulated tapioca or potato starch in rawcondition to 20 pounds of a 30% solution of water-soluble adhesive, suchas dextrine derived from tapioca. The dextrine serves the function offixing the raw starch granules to the fabric, so that they do not tendto shed from the fabric as a dust. We preferably employ raw tapioca o rpotato starch, for the reason that these starches tend to yield, uponcooking, adhesive solutions of higher. viscosity than those preparedfrom other raw starches. The starch composition preferably contains asuitable preservative, such as beta naphthol, which inhibitsputrefaction o r moulding of the starchy materials. The starchcomposition may be applied in any suitable way, as by spraying orcoating onto the fabric, or by immersing the plied, stiffened sheet in abath of the composition. The water-soluble adhesive thus furnished oneither or both faces of the stiifener makes it possible to attach' thestiffener to either or both the shoe upper and the shoe lining,wherefore, the stiffener, once put in the shoe, will tend to remainintegrated with the shoe upper.

On the accompanying drawing,

Figure 1 illustrates diagrammatically and conventionallyinstrumentalities which we may employ in making our plied, stiffenedsheet.

Figure 2 shows in' perspective our nished box toe blank, partiallybroken away and appropriately legended to indicate its componentelements.

As shown in Figure 1, two rolls of fabric I are simultaneously unwoundand progressively fed in opposite directions into the ,nip of a pair ofcalender rolls 2. These rolls are rotated. at the same speed but inoppositedirections, and clear each other sufficiently to permit thestiffening composition of the character described to be calendered inbetween the fabric sheets as a unifoim layer of the desired thickness,the pressure of calendering being all that is necessary to cause thelayer to be enmeshed by the fabric sheets.

The stiifening composition may be constantly kept as a -bank or supply 3at the flared entrance to the nipof the rolls, so that a plied,stiffened conducted over the guide roll 5 under the roll 6 v maintainedpartially submerged in a bath 'l of adhesive solution such as alreadydescribed. The outer fabric plies of the sheet thus become charged witha solution of water-soluble adhesive. Upon emerging from the bath l, thesheet may be passed over a guide roll 8 and into a drierr 9 of anysuitable design. The dried sheet may then be cut into box toe blanks I0,which, as shown in Figure 2, may be skived at their marginal edges I i,as ordinarily.

It is possible to use iiexible sheets other than woven ones, such4 asfelts or papers reinforced. if desired, with rubber or other bindingagent, leather, cellophane, etc., as backings for the stiffeningcomposition, but we prefer to use a woven textile fabric, because itaffords a backing which is not only resistant to tearing and otherphysical stress, butto which the stiffening composition becomes firmlyanchored by enmeshyment and which permits of the desired degree of beasphalt, rosin, Wax, cumar, articial resins,l

or mixtures of such substances, which undergo softening or iuxing underthe application of only moderate heat, such as that furnished by livesteam, and which quickly set at normal temperature conditions to a solidcondition. In the case of hard, stiff box toes, such as we are desirousof producing, the thermoplastic agent should be used in an amountdistinctly in excess of the rubber. Montan wax can be used to advantageas the only thermoplastic agent, in an amount about twice that of therubber, to yield, as hereinbefore described, a stiffening compositionwhich functions to impart to the stiifener of the present invention ahigh degree of hardness and stiffness. Aside from the function of theouter, exible sheet backings in keeping the layer of thermoplasticcomposition connedi therebetween so that there is little tendency for itto break away under bending or iiexing action, they serve the purpose ofenhancing the over-al1 stiffness of the box toe blanks. In the case ofwoven textile fabrics or other sheet backings which have been .coated orcharged with a watersoluble adhesive, such as starch, as hereinbeforedescribed, the water-soluble adhesive enhances the stiffness of thefabric and, being substantially unaifected by temperature changes, suchas would soften theintermediate layer of' thermoplastic composition, isof further value in rendering the toe portion of the nished shoecontaining the moulded box toe blank resistant to deformation under theaction of direct solar heat or under exposure to warm atmospheres, suchas would causemore or less softening of the intermediate thermoplasticlayer.

We claim:

1. A box toe blank capable of being rendered limp and mouldable undermoist heat, comprising a backing of flexible sheet material -to which isanchored a continuous, calendered layer of thermoplastic compositioncontaining rubber, said backing being charged with raw starch granules.

2. A box toe blank c ble of being rendered limp and mouldable unde-moist heat, comprising a backing or nexibie sheet material to which b15is anchored a continuous, calendered layer o! thermoplastic compositioncontaining rubber,

soluble adhesive. Y 3. A box toe blank capable oi' being rendered limpand moldable under moderate heat. comprising' outer fabricbacklngscarrying there-- between a calendered layer of a thermoplasticstiffening composition containing rubber, the fabric backings being ofsufnciently coarse mesh. to ensure firm anchorage thereto of thecalendered layer of thermoplastic stiiiening composition. e

, 3 4. A box toe blank capable of being rend limp and moldable undermoderate heat, comprising outer fabric backings carrying therebetween a`calendered layer of a thermoplastic stiilening composition containingrubber, V the fabric backings being of sumciently coarse to ensure rmanchorage thereto of the calendered layer o1' thermoplastic stiieningcomposition and. at least one of said backings being undergoes adhesiveactivation under moist heat.

HAROLD S. HOLLIS E. GOODWIN, STANLEY P, LOVELL.

with a water-soluble adhesive that 1o

